In a scroll compressor, spiral walls of a fixed scroll and a revolving scroll are interlocked, and the revolving scroll orbitally revolves around the fixed scroll so as to gradually reduce the volume of a compression chamber formed between the walls to compress a fluid inside the compression chamber. In such scroll compressors, since it is possible to improve the compression ability by increasing the compression ratio without increasing the size of the compressor itself, a scroll compressor with a scroll member having a step-like shape is put to actual use (for example, refer to Patent Document 1.    Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2003-35285